Telephony.



E. R. GORWIN.

TELEPHONY. APPLICATION FILED JAN.13, 1910. RENEWED JUNE 2, 1911.

1, Q3Q504, Patented June 25 1912.

or is being called by another ELMIER R, COLRWIN, 0351" CHICAGO, ILLINOIS, ASSIGNOR TO CORWIN TELEPHONE MANU I FACTURING CGI IPANY, Gill CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TETJEPEIONY.

Specification of Letters Yatent. Application filed January 13, 1910, Serial No. 537,846.

Patented June 25, lJlQ. Renewed June 2, 1911. Serial No. 630,920.

To all whom 2 may concern: I

Be it known that 1, Emma It. CORWIN, citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new 11nd useful Improvement in Telephony, of which be following is a. full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a. part of this specification.

My invention relates to telephone systems wherein parties at substations may estal lish connections between the substations yyithout the intervention of telephone exchange equipment, such systems being com-- monly known as interconnnunicating systems or interior systems, it being understood that I do not limit myself to a system housed exclusively in one building.

My invention has a number of objects and advantages in view among "which are the provision of means whereby a party seeking connection with a line that is in telephonic connection with another or that is calling; party is no prised of the condition of the line he seeks by means of a busy signal, and the provision of means for preventing telephone stations from being capable of telephonic connection with another telephone station which is calling or is in the process of being called or is in telephonic connection with another station.

I will explain my invention and further features thereof more fully by reference to the accompanying drawing showing the prefGlTGCl embodiment thereof system having three telephone stations, though I do not wish to be limited to the number oi. telephone stations that may be embodied in the system. The three stations are designated No. 1, No. 2 and No. 3, the telephone line extending from each of the stations being metallic, to which character istieI do not Wish to be limited. Station No. 1 thus has a metallic line 1 1 extending therefrom to each of the other stations. Similarly, station No. 2 has a telephone line 2 2 extending to each of the other stations, and station No. 3 has a telephone line 3 8 extending to each of the other stations. At each station there is a line selecting key 0 individual to each of the other lines, whereby each station may select any of the other stations, providing that the station to be as applied to a more 111 detail.

selected is free for selection. Each select.- ing key is also preferably adapted to cause the operation of the signal receiver at the selected station. novel feature of my present invention, each key, whether itis adapted to select or operate the signal receiver at the selected station or is adapted both to select and operate the signal receiver at the selected station, is also adapted to cause the manifestation of a busy signal in the event of selection of station that is calling or has been called or is in connection with another. The circuits and apparatus, by which theresults above outlined are accomplished will be later explained.

There is an electro-magnet Z) at each station whose oflice is to establish con11nunication between calling and called stations when the called station is free to be selected, the magnet b at the calling stat-ion being the one that is operated for this purpose. There is also an electro-n1agnet c at each station, such magnet at a calling station hem operated when the called station is not. free for selection for the purpose of establishing a busy test condition to apprise such calling station-that the called station is not free for selection. The magnet 0 also serves to break or prevent the telephonic connection of the calling party that is endezworing to select a called station that is not free for selection. The circuits and apparatus by which the magnets Z) c perform their functions will later be explained.

The system illustrated is a common battery system, to which however I do not wish to be limited. The common battery is illu. trated at d. I preferably, though not'neec'ssarily, employ a source ofcurrent which is adapted to be used both for testing and for signaling, this source of current being illustrated at c. A circuit interrupting electromagnetf is used for modifying the current from the battery 6 for testing purposes.

llaving thus generally indicated some of the prominent of my invention, I will now embodiment of the invention describe the In the drawing, station No, l is an origi nal calling station, station No. 2 is a station that has been selected and called by station No. 1, station No. 2 l'iaving been free for selection, the magneto at station No. 1 be- In accordance with. oneillustrated characteristics of the system i 1 stations, V

ing free to operate station No. 1 and station No. 2. Station No. 3 is a stat-ionwhich isillustrated in the act of endeavoring to select one of the other station No. 1 in this instance. The station sought by station No. 3 not being free for selection, magnet 0 at station No. 3 is operated to prevent the connection of the telephone equipment at stat-ion No. 3 with theline that station No. 3 is endeavoring to select, magnet c at station No. 3 at the same time causing the manifestation of the busycondition of the line leading from station The magnets b c at the selected called station No. 2 are not operated.

The party at station No. 1 in initiating connection with station No. 2 first removes his telephone receiver 9 fromhis switch hook and thereafter fully depresses the button a at his station which is individual to line No. 2 extending from station No. 2, and under the assumption that station No. 2 is free for selection, the magnet b at station No.1 is energized as a consequence of the establishment of a circuit therethrough which may be traced from the upper terminal of the battery d through the impedance '2' in the line of the calledstation, in this instance line No; 2, the uppermost contact a of key a that is engaged bythe contact (62 connected with the upper side of the line 2 2 that includes the stated impedance 2' as a consequence of the full depression of the key a at station No. 1, thence through the winding of magnet b to the switch hook h and the contact it that is connected with the lower terminal ofthe battery (Z and which is engaged by the switch hook it at the calling station, been removed from said switch hook. The actuated key a, at station-No. 1 being still fully depressed, the extreme lower contact e of said key (this contact being connected with the upper terminal of the battery 0) is connected with the lower limb 2 of the called line by way of contact a, current from the battery 6 then finding path by way of the contacts 6' a the lower side of the line2 2 and the contacts h h", the circuit for this current continuing from the signal receiver Z to the lower side of the battery c with whichone terminal of said signal receiver is pern'ianently connected. The called party at station No.2, in response to the signal conveyed 'by the device Z (this device. being preferably in the nature of a direct current bell,) moves his telephone receiver 'trom its switch hook. 'lhe calling party, after having maintained his actuated key n depressed sulliciently long to operate the signal recciver l at the called station a proper length of time, releases the actuated key, which thereupon assumes the. position illustrated, the springs engaging the key plunger and forcing the plunger outwardly until the outthe telephone receiver having telephonically to unite I ward movement is arrested by the pin 6 engaging the upper notch in the key. The position which the operated key at station No.

.1 is initially caused to occupy is.similar to the posit-ionoccupied by the key a at station No. 3 that is individual to line 1 1. The pins 6 at each station are provided upon a common bar 6 whereby when any key at a station is depressed, the other keys at said station are released, the pins 6 of such other keys occupying the innermost notches when the connecting bar rises, the return upward movement of the connecting ed by spring mechanism 6. The actuated key at the calling station continues in the position in which it' is illustrated throughout the remainder of the operations and until thebar e is again actuated either pression of this key in case station No. 2 is again called by station No. 1 or until some other key at station No. 1 is depressed in case some other station is to be called. When the actuated key at station No. 1 is in the position shown, the top and bottom contacts are disconnected. The armature it belonging to the magnet b at station No. 1 is attracted in a clockwise direction when circuit is closed through magnet b at station 'No. 1 to move the contacts is which itcarries'into connection with contacts 70 The contact 7r, also carried by the armature 7c, is moved into contact with the contact is. As a consequence of the connections thus effected by the magnet 71 at station No. 1, the transmitter at station No. l is supplied with current from battery cl over a circuit'which may be traced from the upper terminal of the battery (Z through the ilnpedance 2' of the called line 2 2, the contact a, the switch spring (4", the contact 70 station No. 1, the contacts 11. it that are brought into connection by the switch hook it when relieved of the weight of the receiver, the contact Z contacts k If, the winding of magnet 7), the switch hook it, and the contact 71. to the lower terminal of battery (I. The transmitter at the called sta tron No. 2 is supplied with current from the battery (I by way of a circuit which may be traced from the upper termlnal of the battery (I through the impedancei in the upper side of line 2 2, the contact fir nor-m'ally connected with the contact lt'flthe transmitter and receiver at station No. 2, the contacts It It at station No. 2, the receiver 1 atsaid by the full as the contact In, the telephone transmitter and receiver at calling bar being efi'ect-' station being removed from its switch hook,

the lower side of line 2 2, the contacts a" a of the depressed button at station No. l, the contacts Zr at station No. l,the winding of magnet b at stationNo. 1, the switch hook /z and the contact- It at station No. 1,t-o the lower terminal of the battery (Z. The transmitters are thus supplied with current or energy, but I do notwish to be limited to the use of common battery for the purpose of supplying the transmitters with energy. Telephonic connection between the calling and called stations may be traced for example from the transl'nitter at station No. 1 through the contact k at station No. 1, the contact Z2 at station No. l, the switch spring a atstation N0. 1, the contact a at station No. 1, the upper side of line 2 2, the contact li at station No. 2, the contact .713 at. station No. 2, the transmitter and receiver at station No. 2, contacts If lfl'at station No. 2, the lower side of line 2 2, contacts a a at station No. 1, contacts is is 'at'station No. 1, and back to the transmitter at station No. 1. The arrangement is 1 referably such that the calling station may maintain the selected operating key fully depressed until the called station responds, the establishntient of the signaling circuit in no wise interfering with the establishment of the telephonic circuit occurring when the party at the called station removes his receiver from its switch hook, the calling station ascertaining that the called station has heard the signal when the party at the called station speaks into his transmitter. The arrangement is also such that the continued presence of the signaling circuit in no wise interferes with the test and'lockout features of my invention.

I have thus fully described how a calling station may select and signal a station that is free for selection, this result being permitted owing to the normal idle position of the armature is at the called station. I will now describe the specific means illustrated for preventing a station from having telephonic connection with either the cal ing station No. 1 or the'called station No. 2, and whereby a busy condition is manifcsted'at the third station.

From the drawing and the description thereof which has been furnished, it will have been observed that the switch hook contact h" at each station is in permanent connection with the lower terminal of the common battery d, and that the upper ter-,

minal of said common battery is connected with the lower side of the calling line, line No. 1, and the lower side of the line extending to "'f'the station, station No. 2, that has been called. An inspection of the drawing will show that the lower terminal of each magnet 0 is adapted to be connected with the lower terminal ofthe battery 0! by way of the corresponding switch hook and the contact h when engaged by such switch hook.'

The upper terminal of each magnet c is connected with-a contact m which is engaged by theeontact spring a when the bar 6 associated with such spring is depressed, partially or fully. springc at each station is permanently connected with the springs a at such station,

result being that when either of the The contact' keys at station No. 3 is fully depressed, the terminal at of the magnet r at such eta-- tion is connected with the lower limb of line 1 it or the lower limb of line 2 2 according to the key that is depressed, and

through such limb with the upper terminal of-the battery (1, whereby the magnet c is energized to move its armature which 1s the same armature that is provided for 1 l or 2 2. A circuit is however established through the telephone apparatus at station No. 3 that includes the batterym and the circuit making and breaking magnet f, whereby a characteristic test signal is manifested in the receiver at station No. .3 to indicate to the party at saidstatiozl that the line desired is busy. This circuit may be traced from the lower terminal of the battery 6 through the engaged contacts '22 at station No. 3, the telephone receiver g at said station, the telephone transmitter at saidstation, the engaged contacts 0, the circuit making and breaking magnet f and its armature switch, to the upper terminal of the battery 6. The telephone receiver 5, is the preferred device for responding" to the testing current, but I do not wish to be limited, to this device for this purpose. Testing current is thus supplied to a responsive device at a calling station seeking connection with a busy line without having such. testing current impressed upon the busy line, the test circuit being purely local or preferably conductively independent of thelline tested. Though. the contacts (2" m at acalling station seeking connection with a linefree to'be selected are engaged when the key individual to the line being selected is actuated, yet the magnet c at such station does not have circuit closed thcrethrough, owing to the fact that there ,is a

gap at h h at the selected station, station No. 2, in the path between the magnet c and the upper terminal of the battery (Z. When theselected party responds, the magnet cat the calling station, station No. 1, may thereupon or thereafter be energized providing the bar 6 is depressed, but such magnet 0 cannot alter the posit-ion. of the armature In, which is only effectively sub ject to the influence of the magnet 71, during the time that the calling party at-sta tion No. 1 has his telephone receiver removed from its switch book. When the calling party restores his receiver, circuit for the magnet Z) is opened at 71., and since the contacts 6' m at the calling station, station No. 1, are then separated. the arma- 'catedfor the armature Ii:

ture'. is is restored to its normal neutral position, such a neutral position being indiat station No. 2. In order to prevent false operation of the magnet 0, the plungers of the keys have a sufiicient amount of lost motion with respeet to the springs of the keys so that the depressed will 3 key which is being fully occasion downward movement of the bar e to release all the other keys associated with said bar and permit the plungers thereof to be thrust to their outermost positions I before the switch contacts of the key that is being operated are actuated, circuit for w the magnet 0 then being most positively party first endeavored to select.

\Vhile I have shown keys individual to the ditterentlines at the different stations, I-do not wish to be limited thereto in the strict significance. of the term, and I therefore use the term switches in the claims in a broad sense.

From the description which has been given,

telephone lines. each extending to. the stations of the other lines. switches at each station of each oi said lincs individual to the remaining lines. and electro-magnetic apparatus at each of the stations gm'crncd by said switches 'for bringing about tolephonic conncction bctwccn the telephone stat-ions oi." the ditl'crcnt lincs. such apparatus at the called station when in normal condition cooperating with apparatusl'at a alling station when a tuated to permit tclephonic communication between the calling "and'called stations.

vot my invention,

\Vhile l'havc hcrcin shown and particularly described the preferred cmlaalimcnt i do not wish to vbc limited to the precise arrangement shown, as changes may rcadily be made without dcparting itronr the spirit of my invention, but,

llaviiig thus dcscribcd my invcntion, I claim as new and desire to secure by Letters Patent the following: -v i l. A telephone system including three or moretelephone lincs. cach extending to the stations of the othcr lines, switches at each station of each ot said lines individual to the remaining lines, apparatus at ach oi the stations governed by said switches [or bringing about telephonic connection be it will be seen that I have provided a telephone system including three or more 1 tweenthe telephone stationsof the different lines,-, such apparatus at the called station when in normal condition cooperating With apparatus at acalling station when actuated .to permit telephonic communication between thecalling and called stations, and; a talking battery common to said lines.

2. A telephone system including three or more telephone lines, each extending to the stations of the other lines, switches at each station of each bf said lines individual to the remaining lines, electromagnetic appaatus at each of the stations governed by said switches for bringing. about telephonic connection between the telephone'stations of the different lines, such apparatus at the called station when in normal condition cooperating with apparatus at a calling sta--' tion when actuated to permit telephonic communication between the calling and called stations and a talking battery common to said lines.

A telephone system including three or more'telephone lines, each extending to the stations of the other lines, switches at each station ot' each of said'lines individual to the remaining lines,"apparatus at each of the stations governedby said switches for bringing about telephonic connection between the telephone stations of the different lines. and means jointly controlled by the muipment of a busy line and the equipment of a line seeking connection with such busy line for establishing a busy test which is in-' dependent of the lines. V

t. A tclcphonc systemincluding three or:

more telephone lines, each extending to the I stations of the other lines. switches at each station of each of said lincs individual to the remaining lines, apparatus at each of the stations governed by said switches for bringing about telephonic connection between the telephone stations of the different lines, and means, jointly controlled by the equipment of a busy line and the equipment of a line seeking connection with such busy line for establishing a. busy test circuit which is indcpem'lent of the lines.

5. A telephone system including three or more telephone lines. each extending to the stations of the other lines, switches at eacli station of each oF said lines individual to the remaining lines. apparatus at'each of the stations governed by said switches for bringing about telephonic connection between the telephone stations oftlie difiere'nt use lines, and means governed by each switch.

when actuated at a calling the remaining lines, apparatus at each of the stations governed by said switches for bringing about telephonic connection between the telephone stations of the different lines, such apparatus at the called station when in normal condition cooperating with apparatus at: a calling station when actuated to permit tClQPllOIllC COITIIDLHilCtltlOIl loctwccn the calling and called stations, and mains governed by each switch when actuated. at a calling station for establishing a busy test condition in association with the calling line and the line selected by the calling line.

7 A telephone system including three or more telephone lines, each extending to the stations of the other lines, switches at each station of each of said lines individualto the remaining lines, clectro-inagnct-ic appae' ratus at each of the stations governed, by said switches for bringing about telephonic connection between the telephone stations of the differentlines, such apparatus at the called station when in normal condition cooperating withapparatus at a calling station when actuated to permit telephonic communication between the calling and called stations; and means governed. by each switch when actuated at a calling station for establishing; a busy test condition in association with the calling line and the line selected by the will; line. 7

S. teieohoi ye including three or more telephone t. e emu. extending to the stations of the otheciines, switches at each station of each of said lines individual to the reniaininglines, apparatus at each. of the stations for bringing about telephonic connection he"? the telephone stations of the dillertm. lines, and means governed each switch when actuated at a calling i. said lines inclis ithial naming apparatus at each of ionsgovcri. ed by said switches for about tch uhonic connection x e tele iihone stations the diticr an i .oieaiiis 'iointly controlled by th its]? line and the equip! connection with sue out telephone em including, three on each extending to the lines, switches at each. lines individual to the remaining lines, apparatus at each of the stations; governed by SWZtCl'lQS for bringing; about telephonic connection bei [L station ol eaci l tween the telephone stations of the different lines, and means governed by each switch when actuated at a calling station for look ing out the telephone of a line seeking the line of the calling station and the line selected by the calling station.

' 11. A telephone system including three or more telephone lines, each extending to the stations of the other lines switches at each station of each of said lines individual to the remaining lines apparatus at each of the stations governed by said switches for bringing about telephonic connection between the telephone stations of the ditierent when in normal condition cooperating with a ppara tusat a calling station when actuated to permit telephonic communication between the calling and called stations, and means governed by eachswitch when actuated at a calling station for locking out the telephone of a line seeking the line 01" the calling station and the line selected. by the calling station. l y

'12. A telephone system including three or more telephone lines, each extending to the stations of theother lines, switches each station of each of said lines individual to the remaining lines electromagnetic apparatus at each of the stations governed by said switches for bringing; about telephonic connection between the telc 'ihonc statio' s o (litter-silt lines Fit h. appoint: station when. innorn'ial condition coop inn with apparatus at a calling? when curated to permit teiephonie communication hetwcen the calling and call stations, i means gt'flflf'llfiit by W swi ch when actuated. at a calling at? in for loo .hg out the telephone of a line s el=.ing the the of i calling tion and the line selected by" 1 calling station,

A telephone s i tern incl uiino; more telephone lines, each or; statioi'is of the Ollie lines, station of each of said lines inol ideal the .Ftil'tfiitililfg lines apparatus at one oi? the stations govern d r said switches for hiring-- a'ooul. to no coon to eph of the t means by each switch. a

w ,tation t' inching *7 line in: iii-chad i 11;: to if c ea h extent l:

' 4 at each "her lines, so

remaining lin stations governed I m about tele 'zhonic co lines, such apparatus at the c i mat coi'idition cooperatin with tines such apparatus at the called stat-ionwhen norapparatus at a calling station when. actuated to permit telephonic communication between the calling and called stations, and means governed by each switch when actuated at'a calling station for locking out the telephone of a line seeking the line of the calling station.

15. A'telephone system including three or 'more telephone lines, each extending to the stat-ions of the other lines, switches at each station of each of said lines individual to the remaining lines, elect-ro-magnetic apparatus at each otthe stations governed by said switches for bringing about telephonic .con-

nection between the telephone stations of the stations of the other lines, switches at each station of each of said lines individual to the remaining lines, apparatus at each of the stations governed by said switches for bringing about telephonic connect-ion between the telephone stations of the different lines, and

means governed by each switch when actuated ata calling station for locking out the telephone of a line seeking the line selected by the calling station.

17. A telephone system including three or more telephone-lines, each extending to the stations of the other lines, switches at each station of each of said lines individual to the remaining lines, apparatus at each of the stations governed by said switches for bringing about telephonic connection between the telephone stations of the diiferent' lines, such apparatus at the called station when in normal condition cooperating with apparatus at a calling station when actuated to permit telephonic communication between the calling and called stations, and means governed by each switch when actuated at a calling station. for locking out the telephoneof a more telephone line seeking the line selected by the calling station.

18. A telephonesystem including three or lines, each extending to the stations of the other lines, switches at each station of each of said lines individual to the remainin lines electro-ma 'netic a aratus at each of the station's governed by said switches for bringing about telephonlcconmotion between the telephone stations of the ditferenta-lines, such apparatus at the called station when in normal condition cooperating with apparatus at a calling station when actuated to permit telephonic communication between the calling and called stations, and means governed by each switch when actuated at a calling stationfor locking out the telephoneof a line seeking the line selected by the calling station.

19. A telephone system including three or more telephone lines, each extending to the stations of the other lines,switches at each station of each of said lines individual to the remaining lines, apparatus at each of the stations governed by said switches for bring ing about telephonic connection between the telephone stations 'of the different lines and for establishing a busy test condition and mechanism at each station governed by the switches thereat for preventing false busy tests.

20. A telephone system including three or more ielephone lines, each extending to the stations of the other lines, switches at each station of each of said lines individual to the remaining lines, apparatus at ach of the stations governed by said switches for bringing about telephonic connection between the telephone stations of the different lines and for locking out the telephone ofa line'seeking a busy line, and mechanism at each. station governed by theswitclies thereat for preventing improper lockcuts.

In witness whereof, I hereuntosubscribe my name this 11th day of January, A. D., 1910. t

- ELMER'R. CORWIN.

V lVitnesses:

G. L. CRAGG,

R. E. ATHER'roN. 

